Re: [RFC PATCH 0/9] Convert JFS to use iomap

[Dave Chinner <david@fromorbit.com>]

On Thu, May 26, 2022 at 08:29:01PM +0100, Matthew Wilcox (Oracle) wrote:
> This patchset does not work.  It will eat your filesystem.  Do not apply.
> 
> The bug starts to show up with the fourth patch ("Convert direct_IO write
> support to use iomap").  generic/013 creates a corrupt filesystem and
> fsck fails to fix it, which shows all kinds of fun places in xfstests
> where we neglect to check that 'mount' actually mounted the filesystem.
> set -x or die.
> 
> I'm hoping one of the people who knows iomap better than I do can just
> point at the bug and say "Duh, it doesn't work like that".
> 
> It's safe to say that every patch after patch 6 is untested.  I'm not
> convinced that I really tested patch 6 either.

So the question I have to ask here is "why even bother?".

JFS is a legacy filesystem, and the risk of breaking stuff or
corrupting data and nobody noticing is really quite high.

We recently deprecated reiserfs and scheduled it's removal because
of the burden of keeping it up to date with VFS changes, what makes
JFS any different in this regard?

i.e. shouldn't this patchset be an indication that we should be
seriously considering deprecating and removing more legacy
filesystems rather than taking on the risk and burden associated
with updating them to modern internal kernel interfaces?

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com